JP2019053020A - Inspection method, device, system and program - Google Patents

Abstract

To provide an inspection method with which it is possible to accurately detect a defect in a transparent inspection target.SOLUTION: A lighting device 2 displays a lighting pattern on a display surface, an imaging device 5 captures the image of a transparent inspection target lighted by the lighting pattern, and a processor generates a plurality of lighting patterns in which the phase difference of irradiation intensity is constant for at least two kinds of pattern that are periodic along mutually different directions, outputs an instruction to capture, for each of multiple kinds of pattern, the image of an inspection target 10 lighted by the plurality of lighting patterns and acquire the captured image to the imaging device, and exercises synchronization control for causing the operations of the lighting device and the imaging device to be synchronized. The processor superimposes the amplitude change of brightness of the captured image of the inspection target lighted by the plurality of lighting patterns for each of multiple kinds of pattern, and detects a defect of the inspection target on the basis of the result of comparison of the amplitude change of brightness of the superimposed captured images with the amplitude change of brightness of captured images previously superimposed on a reference target for each of multiple kinds of pattern.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an inspection method, apparatus, system, and program.

  Transparent members are used in various fields. A transparent member such as a transparent cover that covers a part of the device has various shapes and is provided in a lighting device having a lighting function, a display device having a display function, or the like. The transparent member may be used for dustproofing, waterproofing, protection, or the like, but it is desirable that the transparent member does not interfere with the illumination function and display function by transmitting light. For this reason, it is desirable to provide a transparent member free of defects.

  The defects of the transparent member include defects such as scratches, unevenness, and foreign matter existing inside the transparent member, and defects such as scratches, unevenness, and foreign matter existing on the surface of the transparent member. When these defects are inspected visually, the transparent member is illuminated, but depending on the surface shape of the transparent member, the inspection is likely to be affected by the background and surroundings of the inspection object. In particular, when the surface shape of the transparent member is complicated, for example, it is difficult to visually inspect and it is difficult to accurately detect defects.

  In view of this, an inspection method has been proposed in which a transparent member is inspected with an inspection apparatus to detect a defect in the transparent member. The inspection apparatus illuminates the transparent member with light from the light source, captures an image of the transparent member with the imaging device, and detects a defect in the transparent member from the captured image. In this case, compared with visual inspection, the sensitivity of the inspection is stabilized, the inspection can be performed at high speed, and the inspection cost can be reduced. However, even if an inspection device is used, depending on the surface shape of the transparent member, the inspection is likely to be influenced by the background and surroundings of the inspection object, and inspection is performed in an environment dedicated to inspection that does not receive these influences. It is difficult to accurately detect defects unless measures such as performing the above are taken.

JP 2013-108944 A JP 2006-267022 A JP 2002-323454 A

  In the conventional inspection method, since the inspection object is transparent and has various surface shapes, the inspection is easily influenced by the background and surroundings of the inspection object, and it is possible to accurately detect defects in the transparent inspection object. difficult.

  Therefore, an object of one aspect is to provide an inspection method, apparatus, system, and program capable of accurately detecting a defect to be transparently inspected.

  According to one proposal, the illumination device displays an illumination pattern on a display surface, the imaging device captures an image of a transparent inspection target illuminated by the illumination pattern displayed on the display surface, and the processor Generating a plurality of illumination patterns having a constant irradiation intensity phase difference for at least two types of patterns periodically along different directions, and the plurality of illumination patterns for each type of pattern. An instruction to display the image on the display surface to the illuminating device, and an instruction to capture the image of the inspection target illuminated with the plurality of illumination patterns for each type of pattern to obtain a captured image. And performing synchronization control to synchronize the operation of the illumination device and the imaging device, and the processor performs the plurality of illumination patterns for each type of pattern. The amplitude change of the brightness of the captured image of the inspection object illuminated by the image is calculated and superimposed, and the processor changes the amplitude change of the brightness of the captured image and the various types of patterns with respect to the reference object. An inspection method for detecting a defect to be inspected is provided based on a result of comparing the amplitude variation of the brightness of a captured image that is calculated and superimposed in advance.

  According to one aspect, it is possible to accurately detect a transparent defect to be inspected.

It is a figure which shows an example of the test | inspection system in 1st Example. It is a block diagram which shows an example of the hardware constitutions of a computer. It is a flowchart explaining an example of the test | inspection process in 1st Example. It is a figure explaining an example of the arithmetic processing with respect to the captured image of the test object in 1st Example. It is a figure which shows an example of the brightness of four captured images which imaged the imaging area of a test object, It is a figure which shows an example of the phase calculation result with respect to the captured image of a test object. It is a figure explaining an example of the arithmetic processing with respect to the captured image of a reference | standard object. It is a figure which shows an example of the brightness of four captured images which imaged the imaging area of the reference object, It is a figure which shows an example of the phase calculation result with respect to the captured image of a reference | standard object. It is a figure explaining an example of the arithmetic processing with respect to the captured image of the test object in 1st Example. It is a figure explaining an example of the test result in 1st Example. It is a figure explaining an example of a test result in the 1st example, and a test result of a comparative example. It is a figure which shows an example of the test | inspection system in 2nd Example. It is a figure explaining an example of a test result in the 2nd example, and a test result of a comparative example. It is a flowchart explaining an example of the test | inspection process in 3rd Example. It is a figure explaining an example of the arithmetic processing with respect to the captured image of the test target in 3rd Example.

  In the disclosed inspection method, apparatus, system, and program, an illumination pattern is displayed on a display surface, a transparent inspection target image illuminated by the illumination pattern displayed on the display surface is captured, and a phase difference in irradiation intensity is constant. Are generated for at least two types of periodic patterns along different directions, and an instruction to display the plurality of illumination patterns on the display surface of the illumination device is provided for each type of pattern. In addition, an instruction to capture an image to be inspected with a plurality of illumination patterns and acquire a captured image is output to the imaging device, and synchronous control is performed to synchronize the operation of the illumination device and the imaging device. Calculates and superimposes the brightness amplitude change of the captured image of the inspection object illuminated with a plurality of illumination patterns for each type of pattern, and changes the brightness amplitude change of the superimposed captured image and the reference object. A defect to be inspected is detected based on a result of comparison with a change in brightness of the brightness of a captured image that is calculated and superimposed in advance for each type of pattern.

  Embodiments of the disclosed inspection method, apparatus, system, and program will be described below with reference to the drawings.

  FIG. 1 is a diagram illustrating an example of an inspection system according to the first embodiment. An inspection system 1-1 illustrated in FIG. 1 includes a lighting device 2, a support unit 3, a controller 4, an imaging device 5, a controller 6, a control device 7, and an input / output device 8. The control device 7 forms an example of an inspection device. The inspection device may include at least one of the illumination device 2 and the imaging device 5. The inspection object 10 is a transparent member, and the surface shape and material are not particularly limited.

  In this example, the illumination device 2 includes a light source 21 that emits light, a mirror 22 that reflects an irradiation pattern from the light source 21, and a transmission screen 23 onto which the irradiation pattern reflected by the mirror 22 is projected. However, the illuminating device 2 will not be specifically limited if it is an apparatus which can display the periodic illumination pattern mentioned later. The illumination device 2 can be formed by a display device (or display panel) that displays a periodic illumination pattern, and the display device is, for example, a well-known liquid crystal display device (LCD: Liquid) having a backlight that is an example of a light source. Crystal Display), organic electroluminescence display devices, and the like. The transmissive screen 23 is an example of a display surface that displays an illumination pattern. In the case of a display device, the display screen is an example of a display surface that displays an illumination pattern.

  The support part 3 will not be specifically limited if it is the structure which can support the test object 10. FIG. In the present embodiment, the illumination device 2 illuminates the inspection object 10 with the irradiation pattern from the lower surface side, which is an example of the first surface of the inspection object 10, and therefore, in the example illustrated in FIG. Has a well-known structure that holds the illumination pattern that illuminates the inspection object 10 above the transmission screen 23 so as not to be blocked. The inspection object 10 may be in contact with the transmission screen 23, or a gap may be provided between the lower surface of the inspection object 10 and the upper surface of the transmission screen 23. In addition, when the support part 3 is formed on a stage having a well-known configuration on which the inspection object 10 is placed and is disposed above the transmission screen 23, the support part 3 is formed of a transparent material. Needless to say.

  The controller 4 is an example of a moving unit that moves the support unit 3 to change the relative position between the support unit 3 and the imaging device 5, and the movement of the inspection object 10 by the support unit 3 according to an instruction from the control device 7. It may have a function of controlling start and end. The controller 4 may be omitted when the support 3 is not moved.

  The imaging device 5 captures an image of the inspection object 10 illuminated by the illumination pattern displayed on the transmission screen 23 of the illumination device 2. In this example, the image of the inspection object 10 captured by the imaging device 5 includes an illumination pattern that has passed through the transparent inspection object 10. The imaging device 5 can be formed by, for example, a well-known CCD (Charge-Coupled Device) camera or the like. The imaging device 5 captures an image from the upper surface side, which is an example of the second surface opposite to the first surface of the inspection object 10.

  The controller 6 is an example of a moving unit that moves the imaging device 5 to change the relative position between the support unit 3 and the imaging device 5, and starts and ends imaging by the imaging device 5 in response to an instruction from the control device 7. It may have a function to control. The controller 6 can be omitted when the imaging device 5 is not moved. When the controller 6 is omitted, the start and end of imaging by the imaging device 5 may be directly controlled by an instruction from the control device 7. Note that when the relative position of the support unit 3 and the imaging device 5 is changed, at least one of the controller 4 and the controller 6 may be omitted. In this example, the captured image captured by the imaging device 5 is supplied to the control device 7 via the controller 6, but may be directly supplied to the control device 7.

  The control device 7 controls the entire inspection system 1-1. The input / output device 8 includes an input device that inputs commands, data, and the like to the control device 7, and an output device that outputs messages, inspection results, and the like. When a command, data, or the like is input from outside the inspection system 1-1, the input device can be omitted. Moreover, when outputting a message, a test result, etc. to the exterior of the test | inspection system 1-1, an output device can be abbreviate | omitted.

  The control device 7 can be formed by a general-purpose computer. FIG. 2 is a block diagram illustrating an example of a hardware configuration of a computer. A computer 100 illustrated in FIG. 2 includes a CPU (Central Processing Unit) 101 that is an example of a processor and a memory 102 that is an example of a storage device. The CPU 101 executes a program including an inspection program stored in the memory 102, and executes an inspection process described later. The memory 102 stores programs, data, and the like. The memory 102 is a portable recording medium such as a USB (Universal Serial Bus) memory, a semiconductor storage device such as a flash memory, a magnetic recording medium, a CD-ROM (Compact Disk-Read Only Memory), a DVD disk (Digital Versatile Disk), etc. It can be formed by a computer-readable recording medium such as an optical recording medium or a magneto-optical recording medium. When a magnetic recording medium such as a disk, an optical recording medium, or a magneto-optical recording medium is used for the memory 102, the recording medium is loaded into a drive such as a disk drive, and the drive reads a program or the like from the recording medium. Write data to the recording medium. In FIG. 2, for convenience, an input / output device such as a touch panel that can be connected to the computer 100 wirelessly or by wire (or an input device and a display device provided separately) is omitted.

  FIG. 3 is a flowchart for explaining an example of the inspection process in the first embodiment. The process shown in FIG. 3 can be executed by the CPU 101 shown in FIG. 2, for example.

  In step S <b> 1 shown in FIG. 3, the CPU 101 controls the controller 4 to move the support unit 3 that supports the inspection object 10 to a predetermined imaging position. When the controller 4 is omitted, the user may manually support the inspection object 10 on the support unit 3 at a predetermined imaging position. In step S1, the CPU 101 may control the controller 6 to move the imaging device 5.

  In step S2, the CPU 101 generates a periodic illumination pattern. In this embodiment, the CPU 101 generates a plurality of illumination patterns having a constant irradiation intensity phase difference for at least two types of patterns that are periodic along different directions. Therefore, the CPU 101 forms an example of a generating unit that generates a plurality of illumination patterns having a constant irradiation intensity phase difference for each of at least two types of patterns periodically along different directions. The at least two types of patterns that are periodic along different directions are not particularly limited, and include, for example, a striped first pattern and a second pattern that extend along different directions. In this case, the striped first pattern and the second pattern extending along different directions may be striped patterns orthogonal to each other. Further, the at least two types of patterns that are periodic along different directions may be patterns such as a rectangular shape, a triangular shape, and a sine wave shape.

  In step S <b> 3, the CPU 101 displays a plurality of illumination patterns generated for one type of pattern on the display surface of the illumination device 2. In this example, the CPU 101 controls the light source 21 to emit the illumination pattern, thereby reflecting the illumination pattern from the light source 21 by the mirror 22 and projecting the illumination pattern onto the transmissive screen 23.

  In step S <b> 4, the CPU 101 controls the controller 6 to move the imaging device 5 to a position where the imaging area of the inspection object 10 is imaged, and image the imaging area of the inspection object 10. In step S4, the CPU 101 may control the controller 4 to move the support unit 3 as well. When the controller 6 is omitted, the user may manually move the imaging device 5 to a position where the imaging area of the inspection target 10 is imaged.

  The CPU 101 illuminates with a plurality of illumination patterns for the same one type of pattern as the process of step S3 for outputting to the illumination device 2 an instruction to display a plurality of illumination patterns on the display surface of the illumination device 2 for one type of pattern. The process of step S4 for capturing an image of the inspection object 10 and outputting an instruction to acquire the captured image to the imaging device 5 is synchronized. That is, the CPU 101 performs synchronous control for synchronizing the operations of the illumination device 2 and the imaging device 5. Therefore, the CPU 101 outputs an instruction to display a plurality of illumination patterns on the display surface of the illumination device 2 for each type of pattern to the illumination device 2 and displays an image of the inspection target 10 illuminated with the plurality of illumination patterns. An instruction to capture an image for each type of pattern and acquire a captured image is output to the imaging device 5 to form an example of a control unit that performs synchronous control to synchronize the operation of the illumination device 2 and the imaging device 5. Thereby, the illuminating device 2 illuminates the inspection object 10 with a plurality of illumination patterns generated for one type of pattern, and the imaging device 5 is inspected with each of the plurality of illumination patterns for the same one type of pattern. 10 images are taken. In this example, the captured image captured by the imaging device 5 is supplied to the control device 7 via the controller 6, but may be directly supplied to the control device 7.

  In step S5, for all types of patterns generated by the CPU 101, it is determined whether or not an image of the inspection object 10 illuminated with each of the plurality of illumination patterns has been captured. If the determination result is NO, the process is step. Returning to S3, if the determination result is yes, the process proceeds to step S6. As a result, for all types of patterns, a plurality of illumination patterns are displayed on the display surface of the illumination device 2, and an image of the inspection object 10 illuminated with the plurality of illumination patterns is captured for all types of patterns. Advances to step S6.

  In step S <b> 6, the CPU 101 calculates and superimposes the amplitude change of the brightness of the captured image of the inspection object 10 illuminated with a plurality of illumination patterns for each type of pattern. In step S7, the CPU 101 determines whether or not all of the imaging areas to be inspected in the inspection object 10 have been imaged. If the determination result is NO, the process returns to step S2, and the determination result is YES. Advances to step S8. Note that if all the imaging regions to be inspected in the inspection object 10 can be imaged by one imaging process, the process of step S7 can be omitted.

  In step S8, the brightness change of the brightness of the captured image superimposed by the CPU 101 in step S6 and the brightness of the captured image that is stored in the memory 102 and is calculated and superimposed in advance for each type of pattern with respect to the reference object. For example, if the difference in amplitude change is equal to or greater than a threshold value, a defect in the inspection object 10 is detected based on the result of comparison with the amplitude change. The reference object is a non-defective product having the same transparent member as the inspection object 10 that has been inspected in advance and has no defects.

  In step S9, the CPU 101 determines whether or not to end the inspection of the inspection object 10. If the determination result is NO, the process returns to step S1, and if the determination result is YES, the process proceeds to step S10. When the inspection of the inspection object 10 is to be ended, for example, the user may input an instruction to end the inspection from the input / output device 8 to the control device 7 (or the computer 100).

  In step S10, the CPU 101 outputs the result of comparison in step S9, that is, the result output indicating whether or not the defect of the inspection object 10 has been detected, to the input / output device 8, and the inspection process ends.

  FIG. 4 is a diagram illustrating an example of a calculation process for a captured image to be inspected in the first embodiment. This calculation process is sometimes called a phase shift calculation process. For convenience of explanation, FIG. 4 shows four patterns in which the phase difference of irradiation intensity (or brightness) is constant at π / 2 (90 °) for a periodic vertical stripe pattern which is an example of one type of pattern. 4 shows four captured images P1 to P4 obtained by imaging an imaging region of the inspection object 10 irradiated with the illumination pattern. In FIG. 4, the black portions indicate that the brightness of the captured images P1 to P4 is low (that is, dark).

FIG. 5 is a diagram illustrating an example of the brightnesses I1 to I4 of the four captured images P1 to P4 obtained by capturing the imaging region of the inspection target 10. The brightness I1 of the captured image P1 is indicated by a solid line, and the captured images P2 to P2 are illustrated. The brightness I2 to I4 of P4 is indicated by a broken line. In FIG. 5, the vertical axis indicates brightness in arbitrary units, and the horizontal axis indicates position in arbitrary units. In FIG. 5, A corresponds to the position indicated by the white broken line in FIG. 4, and B indicates the amplitude from position A to the brightness peak. Further, in FIG. 5, in the portion indicated by the alternate long and short dash line D, distortion occurs in the change in brightness amplitude due to a defect existing in the inspection object 10. In this example, the brightnesses I1 to I4 of the captured images P1 to P4 can be expressed by the following equations when the phase is expressed by φ.
I1 = A + Bcos (φ)
I2 = A + Bcos (φ + π / 2)
I3 = A + Bcos (φ + π)
I4 = A + Bcos (φ + 3π / 2)
In step S6 shown in FIG. 3, when the CPU 101 calculates and superimposes brightness amplitude changes of the four captured images P1 to P4 of the inspection target 10 illuminated with the four illumination patterns with respect to the vertical stripe pattern, for example, Amp = A phase calculation result of 2 × sqrt {(I1−I3) ² + (I2−I4) ² } / (I1 + I2 + I3 + I4) is obtained. FIG. 6 is a diagram illustrating an example of a phase calculation result for a captured image of the inspection object 10. In FIG. 6, the vertical axis indicates the change in brightness amplitude in arbitrary units, and the horizontal axis indicates the position in arbitrary units. In FIG. 6, there is no defect at a position where the change in brightness amplitude is constant. On the other hand, in FIG. 6, there is a defect at a position corresponding to the portion indicated by the alternate long and short dash line D in FIG. 5 where the brightness amplitude change is not constant. In this way, the presence / absence of a defect present in the inspection object 10 and the position of the existing defect can be detected.

  FIG. 7 is a diagram illustrating an example of a calculation process for a reference target captured image in the first embodiment. For convenience of explanation, FIG. 7 shows that the phase difference of irradiation intensity is constant at π / 2 (90 °) for a periodic vertical stripe pattern which is an example of one type of pattern, as in FIG. 4 shows four captured images P1r to P4r of a reference object irradiated with four illumination patterns. In FIG. 7, the black portions indicate that the brightness of the captured images P1r to P4r is low (that is, dark).

FIG. 8 is a diagram illustrating an example of the brightness I1r to I4r of the four captured images P1r to P4r obtained by capturing the reference target imaging region. The brightness I1r of the captured image P1r is indicated by a solid line, and the captured images P2r to P4r. Are indicated by broken lines. In FIG. 8, the vertical axis indicates brightness in arbitrary units, and the horizontal axis indicates position in arbitrary units. In FIG. 8, A corresponds to the position indicated by the white broken line in FIG. 7, and B indicates the amplitude from the position A to the brightness peak. Further, in FIG. 8, since there is no defect in the reference object, there is no distortion in the brightness amplitude change. In this example, the brightnesses I1r to I4r of the captured images P1r to P4r can be expressed by the following equations when the phase is expressed by φ.
I1r = A + Bcos (φ)
I2r = A + Bcos (φ + π / 2)
I3r = A + Bcos (φ + π)
I4r = A + Bcos (φ + 3π / 2)
For example, Ampr = 2 × sqrt {(I1r) is obtained by calculating and superimposing brightness amplitude changes of the four captured images P1r to P4r obtained by capturing the reference target imaging region illuminated with the four illumination patterns for the vertical stripe pattern. ^{-I3r) 2 + (I2r-i4r} ) 2} / (I1r + I2r + I3r + i4r) comprising a phase calculation result is obtained. FIG. 9 is a diagram illustrating an example of a phase calculation result for the reference target captured image. In FIG. 9, the vertical axis indicates the change in brightness amplitude in arbitrary units, and the horizontal axis indicates the position in arbitrary units. In FIG. 9, it can be seen that the change in the amplitude of the brightness is constant and no defect exists.

  In step S8 shown in FIG. 3, the CPU 101 calculates in advance the brightness amplitude change of the captured image as shown in FIG. 6 superimposed in step S6 and each type of pattern stored in the memory 102 with respect to the reference object. Compared with the amplitude change in brightness of the captured image as shown in FIG. 9 superimposed, the phase change of the illumination pattern depending on the surface shape of the inspection object 10 is absorbed, and the amplitude change in brightness is not constant. The changing position is noticeable. Further, since the phase change of the illumination pattern is strongly dependent on the surface shape of the inspection object 10, it is difficult to be influenced by the background and surroundings of the inspection object. As a result, it can be seen that there is a defect at a position where the change in the amplitude of the brightness, which has become noticeable, is not constant, and the presence or absence of the defect of the inspection object 10 and the position of the defect can be accurately detected. . Moreover, since the inspection result does not depend on the judgment of the user, the inspection sensitivity is stabilized. Furthermore, since the above arithmetic processing is relatively simple, the arithmetic processing can be executed in a short time, the inspection can be performed at high speed, and the inspection cost can be reduced.

  By the way, when the defect of the inspection object 10 is, for example, a scratch or the like existing along the same vertical direction as the vertical stripe-shaped irradiation pattern, a plurality of the phase differences of the irradiation intensity are constant for the periodic vertical stripe-shaped pattern as described above. A defect can be detected by performing the phase calculation as described above based on the captured image of the inspection object 10 irradiated with the illumination pattern. However, when the defect of the inspection object 10 is, for example, a flaw existing in a direction different from the vertical stripe-shaped irradiation pattern, for example, the horizontal direction, the phase difference of the irradiation intensity is constant for the periodic vertical stripe-shaped pattern as described above. It is difficult to detect a defect even if the above phase calculation is performed based on the captured image of the inspection object 10 irradiated with a plurality of illumination patterns.

  For this reason, when at least one of at least two types of patterns that are periodic along different directions is a vertical stripe pattern, for example, the other is a periodic stripe pattern along a direction different from the vertical stripe pattern. Thus, the defect of the inspection object 10 can be detected more accurately. The periodic striped pattern along a direction different from the vertical striped pattern is, for example, a horizontal striped pattern orthogonal to the vertical striped pattern.

  In this way, a plurality of illumination patterns having a constant irradiation intensity phase difference are generated for two or more types of patterns that are periodic along different directions, and the inspection target 10 is captured when an image of the inspection target 10 is captured. By illuminating, the defect can be accurately detected regardless of the direction in which the defect of the inspection object 10 extends.

  FIG. 10 is a diagram illustrating an example of a calculation process for a captured image to be inspected in the first embodiment. In this example, there are actually linear defects 502 and 503 in the imaging region 501 of the inspection object 10. As described with reference to FIGS. 4 to 6, for example, four illumination patterns having a constant irradiation intensity phase difference are generated for vertical stripe patterns, and the inspection object 10 is illuminated when an image of the inspection object 10 is captured. An image such as a captured image 504 is captured for each of the four illumination patterns. Therefore, the line defect 502 can be detected from the image 505 after the calculation by performing the phase calculation as described above based on the image such as the captured image 504 captured with respect to the four illumination patterns. On the other hand, the linear defect 503 extends in a direction substantially orthogonal to the vertical stripe pattern as shown by a broken line for convenience in the image 505 after calculation, and is difficult to detect accurately.

  Therefore, as described with reference to FIGS. 4 to 6, for example, four illumination patterns having a constant irradiation intensity phase difference are generated for the horizontal stripe pattern, and the inspection object 10 is illuminated when an image of the inspection object 10 is captured. Thus, an image such as the captured image 506 is captured for each of the four illumination patterns. Therefore, the linear defect 503 can be detected from the post-calculation image 507 by performing the above-described phase calculation based on the image such as the captured image 506 captured for the four illumination patterns. On the other hand, since the linear defect 502 extends in a direction substantially orthogonal to the horizontal stripe pattern as indicated by a broken line in the image 507 after calculation, it is difficult to detect it accurately.

  However, in step S6 shown in FIG. 3, the CPU 101 calculates the amplitude change of the brightness of the captured image of the inspection object 10 illuminated with four illumination patterns for each of the vertical stripe pattern and the horizontal stripe pattern. By superimposing the subsequent images 505 and 507, both the linear defects 502 and 503 can be accurately detected.

  FIG. 11 is a diagram for explaining an example of the inspection result in the first embodiment. FIG. 11 shows a superimposed image 601 after phase calculation for a captured image of the inspection object 10 irradiated with at least two types of patterns periodically along different directions, and a captured image of a reference object irradiated with the same type of pattern as described above. A comparison result 603 between the superimposed image 602 and the superimposed images 601 and 602 after the phase calculation is shown. In this example, it was confirmed from the comparison result 603 that the defect 604 present in the inspection object 10 can be accurately detected.

  FIG. 12 is a diagram for explaining an example of the inspection result of the first embodiment and the inspection result of the comparative example. In FIG. 12, in the image 701 obtained by imaging the imaging area of the inspection object 10 illuminated with the vertical stripe-shaped illumination pattern of the illumination apparatus 2 by the imaging apparatus 5, a defect actually exists in the area surrounded by the broken line 710. It is difficult to determine the presence or absence of defects from one image 701. Note that the stripes in the image 701 do not completely extend in the vertical direction because of the surface shape of the inspection object 10. However, in the superimposed image 702 after the above-described phase calculation for, for example, a total of four images captured using the vertical-striped illumination pattern that is phase-shifted in the same manner as the image 701 of the inspection object 10, it is within the region surrounded by the broken line 710. The defect 604 can be determined, and the defect 604 can also be determined from the superimposed images after the above-described phase calculation on a total of four images captured using the phase-shifted horizontal stripe-shaped illumination pattern. Therefore, the defect 604 can be further conspicuous by superimposing the superimposed image 702 with the vertical stripe-shaped illumination pattern and the superimposed image with the horizontal stripe-shaped illumination pattern. In addition, a phase with respect to a reference object illuminated with the same vertical stripe illumination pattern and horizontal stripe illumination pattern as the inspection object 10, and an image obtained by superimposing a superimposed image 702 with a vertical stripe illumination pattern and a superimposed image with a horizontal stripe illumination pattern. The defect 604 becomes more prominent in the comparison result obtained by comparing the calculated superimposed image with the superimposed image. On the other hand, for example, in the bright field image 703 of the comparative example in which the imaging region of the inspection object 10 illuminated with white light is captured by the imaging device 5, it is determined whether there is a defect present in the region surrounded by the broken line 710. Is difficult. Thus, compared with the inspection using the bright field image 703, according to the present embodiment, it is possible to accurately detect the defect of the inspection object regardless of the surface shape or the like of the transparent inspection object.

  FIG. 13 is a diagram illustrating an example of an inspection system according to the second embodiment. In FIG. 13, the same parts as those in FIG. In the present embodiment, the illumination device 2 of the inspection system 1-2 illuminates the inspection object 10 with an irradiation pattern from the upper surface side, which is an example of one surface of the inspection object 10. Therefore, in the example illustrated in FIG. 3 has a well-known configuration for holding the inspection object 10 below the transmission screen 23. You may form the support part 3 in the stage which has a known structure in which the test object 10 is mounted. In addition, the support part 3 is formed with an opaque material, and has a white upper surface in this example.

  The imaging device 5 captures an image of the inspection object 10 illuminated by the illumination pattern displayed on the transmission screen 23 of the illumination device 2. In this example, the image of the inspection object 10 captured by the imaging device 5 includes an illumination pattern that is reflected on the transparent inspection object 10 and reflected. The imaging device 5 captures an image from the upper surface side which is an example of the one surface of the inspection target 10. The arrangement of the illumination device 2 and the imaging device 5 is not particularly limited as long as the illumination on the inspection object 10 and the imaging of the image of the inspection object 10 do not interfere with each other. Further, when at least one of the support unit 3 and the imaging device 5 moves, the arrangement of the illumination device 2 and the imaging device 5 is not particularly interfered with when the relative positions of the support unit 3 and the imaging device 5 are changed. It is not limited. The control device 7 controls the entire inspection system 1-2.

  Since the inspection process in this embodiment can be performed in the same manner as the inspection process in the first embodiment described with reference to FIG. 3, the illustration and description thereof will be omitted.

  FIG. 14 is a diagram for explaining an example of the inspection result in the second embodiment and the inspection result of the comparative example. In FIG. 14, a defect actually exists in an area surrounded by a broken line 810 in an image 801 obtained by imaging the imaging area of the inspection object 10 illuminated by the vertical stripe illumination pattern of the illumination apparatus 2 by the imaging apparatus 5. It is difficult to determine the presence or absence of a defect from one image 801. Note that the stripes in the image 801 do not completely extend in the vertical direction because of the surface shape of the inspection object 10. However, in the superimposed image 802 after the above-described phase calculation for, for example, a total of four images captured using the vertical stripe-shaped illumination pattern that is phase-shifted in the same manner as the image 801 of the inspection object 10, it is within the region surrounded by the broken line 810. The defect 604 can be determined, and the defect 604 can also be determined from the superimposed images after the above-described phase calculation on a total of four images captured using the phase-shifted horizontal stripe-shaped illumination pattern. Therefore, the defect 604 can be further conspicuous by superimposing the superimposed image 802 with the vertical stripe-shaped illumination pattern and the superimposed image with the horizontal stripe-shaped illumination pattern. Further, a phase with respect to a reference object illuminated with the same vertical stripe-like illumination pattern and horizontal stripe-like illumination pattern as the inspection object 10, and an image obtained by superimposing a superimposed image 802 with a vertical stripe-like illumination pattern and a superimposed image with a horizontal stripe-like illumination pattern. The defect 604 becomes more prominent in the comparison result obtained by comparing the calculated superimposed image with the superimposed image. On the other hand, for example, in the bright field image 803 of the comparative example in which the imaging area of the inspection object 10 illuminated with white light is imaged by the imaging device 5, it is determined whether there is a defect present in the area surrounded by the broken line 810. Is difficult. Thus, compared with the inspection using the bright field image 803, according to the present embodiment, it is possible to accurately detect the defect of the inspection object regardless of the surface shape or the like of the transparent inspection object.

  According to the present embodiment, the same effects as those of the first embodiment can be obtained, and the defect of the inspection object can be accurately detected regardless of the surface shape or the like of the transparent inspection object.

  FIG. 15 is a flowchart for explaining an example of inspection processing in the third embodiment. In the present embodiment, the inspection system 1-1 of the first embodiment shown in FIG. 1 may be used, or the inspection system 1-2 of the second embodiment shown in FIG. 13 may be used. The process shown in FIG. 15 can be executed by the CPU 101 shown in FIG. 2, for example.

  In step S <b> 11 shown in FIG. 15, the CPU 101 controls the controller 4 to move the support unit 3 that supports the inspection object 10 to a predetermined imaging position. When the controller 4 is omitted, the user manually supports the inspection target 10 on the support unit 3 at a predetermined imaging position. In step S11, the CPU 101 may control the controller 6 so that the imaging device 5 also moves.

  In step S12, the CPU 101 generates a periodic illumination pattern. In this embodiment, the CPU 101 generates a plurality of illumination patterns having a constant irradiation intensity phase difference for at least two different patterns of different colors that are periodic along different directions. The different patterns of at least two kinds of colors that are periodic along different directions are not particularly limited. For example, the first pattern and the first pattern of the striped first color extending along different directions A second pattern of a second color different from the color is included. In this case, the striped first color first pattern and the second color second pattern extending along different directions may be striped patterns orthogonal to each other. Further, the patterns having at least two types of different colors that are periodic along different directions may be a rectangular pattern, a triangular pattern, a sinusoidal pattern, or the like. For convenience of explanation, in this example, a case will be described in which the first pattern is a vertical stripe pattern, the first color is blue, the second pattern is a horizontal stripe pattern, and the second color is red. For example, when three patterns having different colors are used, the separation of the respective color components may be facilitated by using the three primary colors red (R), green (G), and blue (B).

  In step S <b> 13, the CPU 101 displays the two illumination patterns generated for the first and second patterns having the same phase on the display surface of the illumination device 2. In this example, two illumination patterns generated for a vertical stripe-shaped blue pattern and a horizontal stripe-shaped red pattern having the same phase are superimposed and displayed on the display surface of the illumination device 2.

  In step S <b> 14, the CPU 101 controls the controller 6 to move the imaging device 5 to a position where the imaging area of the inspection object 10 is imaged, and images the imaging area of the inspection object 10. In step S14, the CPU 101 may control the controller 4 so that the support unit 3 is also moved. When the controller 6 is omitted, the user may manually move the imaging device 5 to a position where the imaging area of the inspection target 10 is imaged.

  The CPU 101 outputs the instruction to superimpose two illumination patterns generated for the first and second patterns and display them on the display surface of the illumination device 2 to the illumination device 2 in this way, The process of step S14 of outputting an instruction to capture an image of the inspection object 10 illuminated by superimposing two illumination patterns of the same phase generated for each of the first and second patterns and acquiring the captured image to the imaging device 5 is performed. Synchronize. That is, the CPU 101 performs synchronous control for synchronizing the operations of the illumination device 2 and the imaging device 5. Thereby, the illuminating device 2 illuminates the inspection object 10 by superimposing two illumination patterns having the same phase generated for each of the first and second patterns, and the imaging device 5 performs the inspection object 10 thus illuminated. The image of is taken. In this example, the captured image captured by the imaging device 5 is supplied to the control device 7 via the controller 6, but may be directly supplied to the control device 7.

  In step S15, it is determined whether or not an image of the inspection object 10 illuminated by overlapping two illumination patterns having the same phase is captured for all the illumination patterns having the same phase generated by the CPU 101, and the determination result is NO. The process returns to step S13, and if the determination result is YES, the process proceeds to step S16. Thereby, two irradiation patterns of the same phase generated for each of the first and second patterns are overlapped and displayed on the display surface of the illumination device 2 for each phase, and two illumination patterns are overlapped for each phase. When the illuminated image of the inspection object 10 is captured for all phases, the process proceeds to step S16.

  In step S16, the CPU 101 separates the blue component from the picked-up image of the inspection object 10 picked up at each phase, and changes the amplitude of the brightness of the picked-up image of the separated blue component (that is, a vertical stripe pattern). Is calculated and superimposed, and on the other hand, the red component is separated and the amplitude change of the brightness of the separated red component captured image (that is, (Amplitude change of brightness of captured image of inspection object 10 illuminated with horizontal stripe pattern) is calculated and superimposed. The processing after separating different types (or colors) of patterns is the same as the processing of the first embodiment or the second embodiment, for example, the same as the processing of the captured images 504 and 506 described with reference to FIG. Good.

  In step S17, the CPU 101 determines whether or not all of the imaging areas to be inspected in the inspection object 10 have been imaged. If the determination result is NO, the process returns to step S12, and if the determination result is YES, the process is performed. Advances to step S18. Note that if all the imaging regions to be inspected in the inspection object 10 can be imaged by one imaging process, the process of step S17 can be omitted.

  In step S18, the brightness change of the brightness of the captured image superimposed by the CPU 101 in step S16 and the brightness of the captured image that is stored in the memory 102 and is calculated and superimposed in advance for each type of pattern with respect to the reference object. For example, if the difference in amplitude change is equal to or greater than a threshold value, a defect in the inspection object 10 is detected based on the result of comparison with the amplitude change. The reference object is a non-defective product having the same transparent member as the inspection object 10 that has been inspected in advance and has no defects.

  In step S19, the CPU 101 determines whether or not to end the inspection of the inspection object 10. If the determination result is NO, the process returns to step S11, and if the determination result is YES, the process proceeds to step S10. When the inspection of the inspection object 10 is to be ended, for example, the user may input an instruction to end the inspection from the input / output device 8 to the control device 7 (or the computer 100).

  In step S20, a result output by the CPU 101 in step S9, that is, a result output indicating whether or not a defect of the inspection object 10 has been detected is output to the input / output device 8, and the inspection process ends.

  FIG. 16 is a diagram illustrating an example of a calculation process for a captured image to be inspected in the third embodiment. In FIG. 16, the same parts as those in FIG. 10 are denoted by the same reference numerals, and the description thereof is omitted. In this example, there are actually linear defects 502 and 503 in the imaging region 501 of the inspection object 10.

  Therefore, in this embodiment, the CPU 101 displays an illumination pattern 903 in which the vertical stripe-shaped blue pattern 901 and the horizontal stripe-shaped red pattern 902 having the same phase are superimposed on the display surface of the illumination device 2 in step S13. Further, the CPU 101 captures an image of the inspection object 10 illuminated with the illumination pattern 903 by the imaging device 5 in step S14. In this example, from the captured image of the inspection object 10 imaged at each of the four phases, on the one hand, the blue component is separated, and the amplitude change of the brightness of the separated captured image of the blue component is calculated and superimposed, On the other hand, the red component is separated, and the brightness amplitude change of the captured image of the separated red component is calculated and superimposed. By separating the blue component, the line defect 502 is detected from the image 505 after the calculation by performing the above-described phase calculation based on the image such as the captured image 504 captured with respect to the illumination patterns having four phases. Can do. In addition, by separating the blue component, the line defect 502 is detected from the image 507 after the calculation by performing the phase calculation as described above based on the image such as the picked-up image 506 taken with respect to the illumination patterns having four phases. can do. By superimposing the calculated images 505 and 507, both of the linear defects 502 and 503 can be accurately detected.

  According to this embodiment, the same effects as those of the first embodiment or the second embodiment can be obtained, and the defect of the inspection object can be accurately detected regardless of the surface shape of the transparent inspection object. Can do. In this embodiment, since the inspection object illuminated with the illumination pattern in which the first and second patterns are superimposed for each phase is imaged, the inspection object illuminated with the first pattern for each phase Compared with the first embodiment or the second embodiment in which the inspection object illuminated with the pattern 2 is imaged, the inspection can be performed at a higher speed because the number of images to be captured can be reduced.

  According to each of the above embodiments, it is possible to accurately detect the defect of the inspection object regardless of the surface shape or the like of the transparent inspection object, and the inspection is stable without being affected by the background and surroundings of the inspection object. Defect detection with high sensitivity. Furthermore, the inspection can be performed at high speed, and the inspection cost can be reduced.

The following additional notes are further disclosed with respect to the embodiment including the above examples.
(Appendix 1)
The lighting device displays the lighting pattern on the display surface,
The imaging device captures a transparent inspection target image illuminated by the illumination pattern displayed on the display surface,
A processor generates a plurality of illumination patterns having a constant irradiation intensity phase difference for at least two types of patterns that are periodic along different directions, and for each type of pattern, the plurality of illumination patterns An instruction to display on the display surface of the illuminating device is output to the illuminating device, and an instruction to capture the image to be inspected illuminated by the plurality of illumination patterns for each type of pattern and acquire a captured image Output to the imaging device, perform synchronization control to synchronize the operation of the illumination device and the imaging device,
The processor calculates and superimposes the amplitude change of the brightness of the captured image of the inspection target illuminated with the plurality of illumination patterns for each type of pattern,
Based on the result of the processor comparing the amplitude change in brightness of the superimposed captured image and the amplitude change in brightness of the captured image superimposed in advance for each type of pattern with respect to the reference target , Detecting the defect to be inspected,
An inspection method characterized by the above.
(Appendix 2)
The inspection method according to appendix 1, wherein the display surface of the illumination device is formed by a transmission screen that projects the plurality of illumination patterns or a display screen of the display device.
(Appendix 3)
The illumination device illuminates the inspection object with the illumination pattern from the first surface side of the inspection object,
The imaging device captures the captured image including the illumination pattern that has passed through the inspection target from a second surface side opposite to the first surface side of the inspection target;
The inspection method according to appendix 1 or 2, characterized by the above.
(Appendix 4)
The illumination device illuminates the inspection object with the illumination pattern from one surface side of the inspection object,
The imaging device captures the captured image including the illumination pattern reflected in the inspection target from the one surface side,
The inspection method according to appendix 1 or 2, characterized by the above.
(Appendix 5)
Supplementary notes 1 to 4, wherein the at least two types of patterns that are periodic along different directions include a first pattern and a second pattern that are periodically striped along different directions. The inspection method according to any one of the above.
(Appendix 6)
The inspection according to any one of appendices 1 to 5, wherein the at least two types of patterns that are periodic along different directions include a first pattern and a second pattern of different colors. Method.
(Appendix 7)
The processor sequentially shifts the phase of the first and second patterns by a certain value to illuminate the inspection object at the same phase at the same time, and illuminates simultaneously with the first and second patterns at each phase. The synchronization control is performed so as to capture an image to be inspected,
The processor separates the color component of the first pattern from the captured image of the inspection target illuminated with the first and second patterns of each phase, and a first amplitude of brightness of the captured image Calculating the change, calculating a second amplitude change in brightness of the captured image by separating the color component of the second pattern,
The processor calculates the amplitude change of the brightness of the captured image on which the first and second amplitude changes are superimposed, and the first and second amplitude changes of the brightness with respect to the reference object calculated in advance. Based on the result of comparing the brightness amplitude change of the superimposed captured image, the defect of the inspection object is detected,
The inspection method according to appendix 6, characterized in that:
(Appendix 8)
Generating means for generating a plurality of illumination patterns having a constant irradiation intensity phase difference for at least two types of patterns that are periodic along different directions;
An instruction to display the plurality of illumination patterns on the display surface of the illumination device is output to the illumination device for each type of pattern, and an image to be inspected illuminated with the plurality of illumination patterns is output for each type of pattern. A control unit that outputs an instruction to capture the captured image and outputs the captured image to the imaging device, and performs synchronization control to synchronize the operation of the illumination device and the imaging device;
With
The control means includes
Computes and superimposes the amplitude change of the brightness of the image to be inspected illuminated with the plurality of illumination patterns for each type of pattern,
Based on the result of comparing the amplitude change of the brightness of the superimposed captured image with the amplitude change of the brightness of the captured image superimposed in advance for each type of pattern with respect to the reference target, the inspection target Detect defects,
An inspection apparatus characterized by that.
(Appendix 9)
The inspection object is illuminated with the illumination pattern by the illumination device from the first surface side of the inspection object,
The captured image including the illumination pattern that has passed through the inspection target is captured by the imaging device from the second surface side of the inspection target opposite to the first surface side.
The inspection apparatus according to appendix 8, characterized by the above.
(Appendix 10)
Additional note 8 or 9, wherein the at least two types of patterns that are periodic along different directions include a first pattern and a second pattern that are periodically striped along different directions. The inspection device described.
(Appendix 11)
The inspection according to any one of appendices 8 to 10, wherein the at least two types of patterns periodic along different directions include a first pattern and a second pattern of different colors. apparatus.
(Appendix 12)
An illumination device for displaying an illumination pattern on a display surface;
A support portion for supporting a transparent inspection object;
An imaging device that captures an image of the inspection target illuminated by the illumination pattern displayed on the display surface;
A plurality of illumination patterns having a constant phase difference in irradiation intensity are generated for at least two types of patterns that are periodic along different directions, and the plurality of illumination patterns for each type of pattern are generated by the illumination device. An instruction to display on the display surface is output to the illumination device, and an instruction to capture an image of the inspection target illuminated with the plurality of illumination patterns for each type of pattern to acquire a captured image is provided. A control device that performs synchronization control to synchronize the operation of the illumination device and the imaging device,
With
The controller is
Computes and superimposes the amplitude change of the brightness of the image to be inspected illuminated with the plurality of illumination patterns for each type of pattern,
Based on the result of comparing the amplitude change of the brightness of the superimposed captured image with the amplitude change of the brightness of the captured image superimposed in advance for each type of pattern with respect to the reference target, the inspection target Detect defects,
An inspection system characterized by that.
(Appendix 13)
A moving means for moving at least one of the support part and the imaging device;
The control device moves the imaging region of the inspection target imaged by the imaging device by changing the relative position of the support unit and the imaging device by controlling the moving unit. 12. Inspection system according to 12.
(Appendix 14)
The illumination device illuminates the inspection object with the illumination pattern from the first surface side of the inspection object,
The imaging device captures the captured image including the illumination pattern that has passed through the inspection target from a second surface side opposite to the first surface side of the inspection target;
14. The inspection system according to appendix 12 or 13, characterized by the above.
(Appendix 15)
Additional notes 12 to 14, wherein the at least two types of patterns that are periodic along different directions include a first pattern and a second pattern that are periodically striped along different directions. The inspection system according to any one of the above.
(Appendix 16)
The inspection according to any one of appendices 12 to 15, wherein the at least two types of patterns that are periodic along different directions include a first pattern and a second pattern having different colors. system.
(Appendix 17)
Display the lighting pattern on the display surface of the lighting device,
Taking an image of a transparent inspection object illuminated by the illumination pattern displayed on the display surface with an imaging device,
Generating a plurality of illumination patterns having a constant phase difference in irradiation intensity for at least two types of patterns periodic along different directions;
For each type of pattern, an instruction to display the plurality of illumination patterns on the display surface of the illumination device is output to the illumination device, and each type of the image to be inspected illuminated with the plurality of illumination patterns An instruction to capture and acquire a captured image for each of the patterns is output to the imaging device, and synchronization control is performed to synchronize the operation of the illumination device and the imaging device,
Computes and superimposes the amplitude change of the brightness of the image to be inspected illuminated with the plurality of illumination patterns for each type of pattern,
Based on the result of comparing the amplitude change of the brightness of the superimposed captured image with the amplitude change of the brightness of the captured image superimposed in advance for each type of pattern with respect to the reference target, the inspection target Detect defects,
A program that causes a computer to execute processing.
(Appendix 18)
The process of displaying on the display surface of the illumination device illuminates the inspection object with the illumination pattern from the first surface side of the inspection object,
The process of picking up an image of the inspection object with an imaging device is performed by taking the captured image including the illumination pattern transmitted through the inspection object from a second surface side opposite to the first surface side of the inspection object. Image,
The program according to supplementary note 17, characterized by that.
(Appendix 19)
The supplementary note 17 or 18, wherein the at least two types of patterns that are periodic along different directions include a first pattern and a second pattern that are periodically striped along different directions. The listed program.
(Appendix 20)
The program according to any one of appendices 17 to 19, wherein the at least two types of patterns that are periodic along different directions include a first pattern and a second pattern of different colors. .

  The disclosed inspection method, apparatus, system, and program have been described above by way of examples. However, the present invention is not limited to the above examples, and various modifications and improvements can be made within the scope of the present invention. Needless to say.

1-1, 1-2 Inspection System 2 Illumination Device 3 Supporting Units 4, 6 Controller 5 Imaging Device 7 Control Device 8 Input / Output Device 10 Inspection Target

Claims (10)

The lighting device displays the lighting pattern on the display surface,
The imaging device captures a transparent inspection target image illuminated by the illumination pattern displayed on the display surface,
A processor generates a plurality of illumination patterns having a constant irradiation intensity phase difference for at least two types of patterns that are periodic along different directions, and for each type of pattern, the plurality of illumination patterns An instruction to display on the display surface of the illuminating device is output to the illuminating device, and an instruction to capture the image to be inspected illuminated by the plurality of illumination patterns for each type of pattern and acquire a captured image Output to the imaging device, perform synchronization control to synchronize the operation of the illumination device and the imaging device,
The processor calculates and superimposes the amplitude change of the brightness of the captured image of the inspection target illuminated with the plurality of illumination patterns for each type of pattern,
Based on the result of the processor comparing the amplitude change in brightness of the superimposed captured image and the amplitude change in brightness of the captured image superimposed in advance for each type of pattern with respect to the reference target , Detecting the defect to be inspected,
An inspection method characterized by the above.   The inspection method according to claim 1, wherein the display surface of the illumination device is formed by a transmission screen that projects the plurality of illumination patterns or a display screen of the display device. The illumination device illuminates the inspection object with the illumination pattern from the first surface side of the inspection object,
The imaging device captures the captured image including the illumination pattern that has passed through the inspection target from a second surface side opposite to the first surface side of the inspection target;
The inspection method according to claim 1, wherein the inspection method is characterized. The illumination device illuminates the inspection object with the illumination pattern from one surface side of the inspection object,
The imaging device captures the captured image including the illumination pattern reflected in the inspection target from the one surface side,
The inspection method according to claim 1, wherein the inspection method is characterized.   The at least two types of patterns that are periodic along different directions include a first pattern and a second pattern that are periodically striped along different directions. 5. The inspection method according to any one of 4 above.   The at least two kinds of patterns that are periodic along different directions include a first pattern and a second pattern having different colors, respectively. Inspection method. The processor sequentially shifts the phase of the first and second patterns by a certain value to illuminate the inspection object at the same phase at the same time, and illuminates simultaneously with the first and second patterns at each phase. The synchronization control is performed so as to capture an image to be inspected,
The processor separates the color component of the first pattern from the captured image of the inspection target illuminated with the first and second patterns of each phase, and a first amplitude of brightness of the captured image Calculating the change, calculating a second amplitude change in brightness of the captured image by separating the color component of the second pattern,
The processor calculates the amplitude change of the brightness of the captured image on which the first and second amplitude changes are superimposed, and the first and second amplitude changes of the brightness with respect to the reference object calculated in advance. Based on the result of comparing the brightness amplitude change of the superimposed captured image, the defect of the inspection object is detected,
The inspection method according to claim 6, wherein: Generating means for generating a plurality of illumination patterns having a constant irradiation intensity phase difference for at least two types of patterns that are periodic along different directions;
An instruction to display the plurality of illumination patterns on the display surface of the illumination device is output to the illumination device for each type of pattern, and an image to be inspected illuminated with the plurality of illumination patterns is output for each type of pattern. A control unit that outputs an instruction to capture the captured image and outputs the captured image to the imaging device, and performs synchronization control to synchronize the operation of the illumination device and the imaging device;
With
The control means includes
Computes and superimposes the amplitude change of the brightness of the image to be inspected illuminated with the plurality of illumination patterns for each type of pattern,
Based on the result of comparing the amplitude change of the brightness of the superimposed captured image with the amplitude change of the brightness of the captured image superimposed in advance for each type of pattern with respect to the reference target, the inspection target Detect defects,
An inspection apparatus characterized by that. An illumination device for displaying an illumination pattern on a display surface;
A support portion for supporting a transparent inspection object;
An imaging device that captures an image of the inspection target illuminated by the illumination pattern displayed on the display surface;
A plurality of illumination patterns having a constant phase difference in irradiation intensity are generated for at least two types of patterns that are periodic along different directions, and the plurality of illumination patterns for each type of pattern are generated by the illumination device. An instruction to display on the display surface is output to the illumination device, and an instruction to capture an image of the inspection target illuminated with the plurality of illumination patterns for each type of pattern to acquire a captured image is provided. A control device that performs synchronization control to synchronize the operation of the illumination device and the imaging device,
With
The controller is
Computes and superimposes the amplitude change of the brightness of the image to be inspected illuminated with the plurality of illumination patterns for each type of pattern,
Based on the result of comparing the amplitude change of the brightness of the superimposed captured image with the amplitude change of the brightness of the captured image superimposed in advance for each type of pattern with respect to the reference target, the inspection target Detect defects,
An inspection system characterized by that. Display the lighting pattern on the display surface of the lighting device,
Taking an image of a transparent inspection object illuminated by the illumination pattern displayed on the display surface with an imaging device,
Generating a plurality of illumination patterns having a constant phase difference in irradiation intensity for at least two types of patterns periodic along different directions;
For each type of pattern, an instruction to display the plurality of illumination patterns on the display surface of the illumination device is output to the illumination device, and each type of the image to be inspected illuminated with the plurality of illumination patterns An instruction to capture and acquire a captured image for each of the patterns is output to the imaging device, and synchronization control is performed to synchronize the operation of the illumination device and the imaging device,
Computes and superimposes the amplitude change of the brightness of the image to be inspected illuminated with the plurality of illumination patterns for each type of pattern,
Based on the result of comparing the amplitude change of the brightness of the superimposed captured image with the amplitude change of the brightness of the captured image superimposed in advance for each type of pattern with respect to the reference target, the inspection target Detect defects,
A program that causes a computer to execute processing.